<!DOCTYPE html>
<html>
<!-- Created by GNU Texinfo 7.1, https://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<!-- Copyright © 2006-2023 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being "Funding Free Software", the Front-Cover
texts being (a) (see below), and with the Back-Cover Texts being (b)
(see below).  A copy of the license is included in the section entitled
"GNU Free Documentation License".

(a) The FSF's Front-Cover Text is:

A GNU Manual

(b) The FSF's Back-Cover Text is:

You have freedom to copy and modify this GNU Manual, like GNU
     software.  Copies published by the Free Software Foundation raise
     funds for GNU development. -->
<title>omp_test_nest_lock (GNU libgomp)</title>

<meta name="description" content="omp_test_nest_lock (GNU libgomp)">
<meta name="keywords" content="omp_test_nest_lock (GNU libgomp)">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<meta name="viewport" content="width=device-width,initial-scale=1">

<link href="index.html" rel="start" title="Top">
<link href="Library-Index.html" rel="index" title="Library Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="Runtime-Library-Routines.html" rel="up" title="Runtime Library Routines">
<link href="omp_005funset_005fnest_005flock.html" rel="next" title="omp_unset_nest_lock">
<link href="omp_005fset_005fnest_005flock.html" rel="prev" title="omp_set_nest_lock">
<style type="text/css">
<!--
a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em}
span:hover a.copiable-link {visibility: visible}
-->
</style>


</head>

<body lang="en">
<div class="section-level-extent" id="omp_005ftest_005fnest_005flock">
<div class="nav-panel">
<p>
Next: <a href="omp_005funset_005fnest_005flock.html" accesskey="n" rel="next"><code class="code">omp_unset_nest_lock</code> &ndash; Unset nested lock</a>, Previous: <a href="omp_005fset_005fnest_005flock.html" accesskey="p" rel="prev"><code class="code">omp_set_nest_lock</code> &ndash; Wait for and set nested lock</a>, Up: <a href="Runtime-Library-Routines.html" accesskey="u" rel="up">OpenMP Runtime Library Routines</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Library-Index.html" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<h3 class="section" id="omp_005ftest_005fnest_005flock-_002d_002d-Test-and-set-nested-lock-if-available"><span>3.44 <code class="code">omp_test_nest_lock</code> &ndash; Test and set nested lock if available<a class="copiable-link" href="#omp_005ftest_005fnest_005flock-_002d_002d-Test-and-set-nested-lock-if-available"> &para;</a></span></h3>
<dl class="table">
<dt><em class="emph">Description</em>:</dt>
<dd><p>Before setting a nested lock, the lock variable must be initialized by 
<code class="code">omp_init_nest_lock</code>.  Contrary to <code class="code">omp_set_nest_lock</code>,
<code class="code">omp_test_nest_lock</code> does not block if the lock is not available. 
If the lock is already held by the current thread, the new nesting count 
is returned.  Otherwise, the return value equals zero.
</p>
</dd>
<dt><em class="emph">C/C++</em>:</dt>
<dd><table class="multitable">
<tbody><tr><td width="20%"><em class="emph">Prototype</em>:</td><td width="80%"><code class="code">int omp_test_nest_lock(omp_nest_lock_t *lock);</code></td></tr>
</tbody>
</table>

</dd>
<dt><em class="emph">Fortran</em>:</dt>
<dd><table class="multitable">
<tbody><tr><td width="20%"><em class="emph">Interface</em>:</td><td width="80%"><code class="code">logical function omp_test_nest_lock(nvar)</code></td></tr>
<tr><td width="20%"></td><td width="80%"><code class="code">integer(omp_nest_lock_kind), intent(inout) :: nvar</code></td></tr>
</tbody>
</table>


</dd>
<dt><em class="emph">See also</em>:</dt>
<dd><p><a class="ref" href="omp_005finit_005flock.html"><code class="code">omp_init_lock</code> &ndash; Initialize simple lock</a>, <a class="ref" href="omp_005fset_005flock.html"><code class="code">omp_set_lock</code> &ndash; Wait for and set simple lock</a>, <a class="ref" href="omp_005fset_005flock.html"><code class="code">omp_set_lock</code> &ndash; Wait for and set simple lock</a>
</p>
</dd>
<dt><em class="emph">Reference</em>:</dt>
<dd><p><a class="uref" href="https://www.openmp.org">OpenMP specification v4.5</a>, Section 3.3.6.
</p></dd>
</dl>



</div>



</body>
</html>
